Green Bar Research Articles

Light-dark Adaptation of Channelrhodopsin C128T Mutant

Channelrhodopsins are microbial type rhodopsins that operate as light-gated ion channels. Largely prolonged lifetimes of the conducting state of channelrhodopsin-2 may be achieved by mutations of crucial single amino acids, i.e. cysteine 128. Such mutants are of great scientific interest in the field of neurophysiology because they allow neurons to be switched on and off on demand (step function rhodopsins). Due to their slow photocycle, structural alterations of these proteins can be studied by vibrational spectroscopy in more detail than possible with wild type. Here, we present spectroscopic evidence that the photocycle of the C128T mutant involves three different dark-adapted states that are populated according to the wavelength and duration of the preceding illumination. Our results suggest an important role of multiphoton reactions and the previously described side reaction for dark state regeneration. Structural changes that cause formation and depletion of the assumed ion conducting state P520 are only small and follow larger changes that occur early and late in the photocycle, respectively. They require only minor structural rearrangements of amino acids near the retinal binding pocket and are triggered by all-trans/13-cis retinal isomerization, although additional isomerizations are also involved in the photocycle. We will discuss an extended photocycle model of this mutant on the basis of spectroscopic and electrophysiological data.

Kyphosus gladius, a new species of sea chub from Western Australia (Teleostei: Kyphosidae), with comments on Segutilum klunzingeri Whitley

Two morphologically distinct forms of the nominal species Kyphosus sydneyanus (Günther, 1886) (Kyphosidae) werediscerned while collecting off Western Australia near Perth in 2009. A morphological comparison with recognized speciesof Kyphosus and an analysis of mtDNA (Cytochrome b, control region, 12S and 16S) and three nDNA markers (RAG1,RAG2 and Tmo-4C4) demonstrated that the more elongate of these forms was an undescribed species of Kyphosus. Itdiffers from congeners in the Pacific and Indian Oceans in the combination of the following characters: green bar on theoperculum, 11-12 dorsal soft fin rays, depth of caudal peduncle 9.9-11.8 % SL, body depth 33.3-41.6 % SL, 55-63 scalesin lateral line, 12-16 interorbital scales, 44-55 pored scales in the lateral line, 3-5 gill rakers on upper limb of first gillarch internally, 11-15 gill rakers on lower limb of first gill arch internally, 15-19 total gill rakers on first gill arch, and byhaving 10 precaudal vertebrae and 16 caudal vertebrae. Examination of museum specimens and available underwaterphotographs suggests that the new species is restricted to Western Australia, and to date it has been recorded between theHoutman Abrolhos Islands and Albany. Discrepancies between the type specimen and original description of Segutilumklunzingeri Whitley made it impossible to determine the relationship between this taxon and the new species from WesternAustralia, and thus we consider S. klunzingeri a nomen dubium.

A new egg-guarding species ofOreophryne(Amphibia, Anura, Microhylidae) from southern Papua New Guinea

A new microhylid frog in the genus Oreophryne is described from southern New Guinea. It is a small species (males to 22 mm snout-urostyle length (SUL), females to 27 mm SUL) distinguished from congeners by having a cartilaginous connection between the procoracoid and scapula, no webs between fingers, basal webs mainly between toes 3 and 4 and between toes 4 and 5, and the fifth toe slightly longer than the third. In life, most specimens have a conspicuous lime green (yellowish in preservative) bar between the eyes, a lime green and irregular longitudinal stripe on the flanks, and an irregular spot of the same colour above the insertion of the upper arms. The advertisement call is a pronounced rattle lasting about one second with a note repetition rate of 26-28 notes per second. Males of the new species guard the eggs of their mates on the underside of leaves hanging 30-400 cm above the ground (© 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Zebrafish inner retina: Local signals for spatial position, luminance, and color contrast

The retina of the zebrafish (Danio rerio) provides an unusually favorable preparation for genetic and developmental studies of the retina. Although the retina has been studied extensively for two decades, the neuronal response of the inner retina is largely unknown. This report describes a prominent local field potential of the inner retina, the Proximal Negative Response (PNR). It is best evoked by small (100 μm) precisely positioned spots of light and is exceedingly sensitive to negative luminance contrast. The polarity, waveform, and other properties of the PNR suggest that it arises primarily from ON-OFF neurons of the proximal retina. The dominant response to negative contrast and its enhancement by light adaptation is believed due to a dominant presynaptic input from OFF bipolar cells. Color contrast was investigated by analyzing responses to a green bar moving on green versus red backgrounds. Over an intermediate range of irradiance, the response to green on red was larger than the response to green on green, thereby providing evidence for the encoding of color contrast. The present findings complement the classic principle of color contrast for human vision known as Kirschmann's third law and bring to mind the view of Walls that color contrast may have been the driving force for the evolution of color vision in lower vertebrates. In sum, the PNR of zebrafish provides clear evidence for the encoding of color and luminance contrast in the inner retina. It exhibits the defining properties common to many other vertebrates, reinforcing the view that the zebrafish may further serve as a model for retinal function and that the PNR may provide a new approach for studies of development, genetics, and retinal degeneration in zebrafish.

The upright posture improves plantar stepping and alters responses to serotonergic drugs in spinal rats

Recent studies on the restoration of locomotion after spinal cord injury have employed robotic means of positioning rats above a treadmill such that the animals are held in an upright posture and engage in bipedal locomotor activity. However, the impact of the upright posture alone, which alters hindlimb loading, an important variable in locomotor control, has not been examined. Here we compared the locomotor capabilities of chronic spinal rats when placed in the horizontal and upright postures. Hindlimb locomotor movements induced by exteroceptive stimulation (tail pinching) were monitored with video and EMG recordings. We found that the upright posture alone significantly improved plantar stepping. Locomotor trials using anaesthesia of the paws and air stepping demonstrated that the cutaneous receptors of the paws are responsible for the improved plantar stepping observed when the animals are placed in the upright posture.We also tested the effectiveness of serotonergic drugs that facilitate locomotor activity in spinal rats in both the horizontal and upright postures. Quipazine and (±)-8-hydroxy-2-(dipropylamino)tetralin hydrobromide (8-OH-DPAT) improved locomotion in the horizontal posture but in the upright posture either interfered with or had no effect on plantar walking. Combined treatment with quipazine and 8-OH-DPAT at lower doses dramatically improved locomotor activity in both postures and mitigated the need to activate the locomotor CPG with exteroceptive stimulation. Our results suggest that afferent input from the paw facilitates the spinal CPG for locomotion. These potent effects of afferent input from the paw should be taken into account when interpreting the results obtained with rats in an upright posture and when designing interventions for restoration of locomotion after spinal cord injury.

Deletion of the Scl +19 enhancer increases the blood stem cell compartment without affecting the formation of mature blood lineages

The stem cell leukemia (Scl)/Tal1 gene is essential for normal blood and endothelial development, and is expressed in hematopoietic stem cells (HSCs), progenitors, erythroid, megakaryocytic, and mast cells. The Scl +19 enhancer is active in HSCs and progenitor cells, megakaryocytes, and mast cells, but not mature erythroid cells. Here we demonstrate that in vivo deletion of the Scl +19 enhancer (SclΔ19/Δ19) results in viable mice with normal Scl expression in mature hematopoietic lineages. By contrast, Scl expression is reduced in the stem/progenitor compartment and flow cytometry analysis revealed that the HSC and megakaryocyte-erythroid progenitor populations are enlarged in SclΔ19/Δ19 mice. The increase in HSC numbers contributed to enhanced expansion in bone marrow transplantation assays, but did not affect multilineage repopulation or stress responses. These results affirm that the Scl +19 enhancer plays a key role in the development of hematopoietic stem/progenitor cells, but is not necessary for mature hematopoietic lineages. Moreover, active histone marks across the Scl locus were significantly reduced in SclΔ19/Δ19 fetal liver cells without major changes in steady-state messenger RNA levels, suggesting post-transcriptional compensation for loss of a regulatory element, a result that might be widely relevant given the frequent observation of mild phenotypes after deletion of regulatory elements.

In vivo accuracy of three electronic root canal length measurement devices: Dentaport ZX, Raypex 5 and ProPex II

To compare in vivo three different electronic root canal length measurement devices: Dentaport ZX, Raypex 5 and ProPex II. Thirty single-rooted permanent teeth scheduled for extraction because of periodontal disease were selected from 10 adult patients (ranging from 45 to 67 years) and divided into three groups of 10 teeth. Before the extraction, an access cavity was prepared and the crown was adjusted to establish a stable reference point for all measurements. The working length in Group 1 was determined using the Dentaport ZX apex locator. A K-file with the largest diameter that could reach the last green bar on the screen was stabilized in the canal using a dual-curable flow resin composite. The same procedure was used for the Raypex 5 (the file reached the last yellow bar) and Propex II (0.0 orange bar) apex locators. The teeth were then extracted and cleared. The distance between the tip of the file and the major foramen was then calculated for each tooth using digital photography according to Axiovision AC software (Carl Zeiss). Positive values were assigned when the file tip passed beyond the major foramen, negative values when the tip was short of the foramen and zero value when the file tip and the foramen coincided. Statistical analysis was performed using the chi-squared test or Fisher's exact test (P ≤ 0.05). Dentaport ZX, Raypex 5 and ProPex ΙΙ produced, respectively, 6, 2 and 4 out of 10 correct measurements, 0, 6 and 5 long measurements and 4, 2, and 1 short measurements. The differences between the three electronic root canal length measurement devices were not significant (P = 0.507). Under the in vivo conditions of this study, the three electronic root canal length measurement devices were not significantly different in terms of locating the major foramen.

TCF/Lef1 activity controls establishment of diverse stem and progenitor cell compartments in mouse epidermis

Mammalian epidermis consists of the interfollicular epidermis, hair follicles (HFs) and associated sebaceous glands (SGs). It is constantly renewed by stem and progenitor cell populations that have been identified and each compartment features a distinct mechanism of cellular turnover during renewal. The functional relationship between the diverse stem cell (SC) pools is not known and molecular signals regulating the establishment and maintenance of SC compartments are not well understood. Here, we performed lineage tracing experiments to demonstrate that progeny of HF bulge SCs transit through other SC compartments, suggesting a hierarchy of competent multipotent keratinocytes contributing to tissue renewal. The bulge was identified as a bipotent SC compartment that drives both cyclic regeneration of HFs and continuous renewal of SGs. Our data demonstrate that aberrant signalling by TCF/Lef1, transcription factors crucial for bulge SC activation and hair differentiation, results in development of ectopic SGs originating from bulge cells. This process of de novo SG formation is accompanied by the establishment of new progenitor niches. Detailed molecular analysis suggests the recapitulation of steps of tissue morphogenesis.

Nonretinotopic processing is related to postdictive size modulation in apparent motion

The present study briefly examined how the perceived size of a leading flash would be modulated by trailing motion signals. Observers were presented with two vertical green bars that were followed by white bars with different lengths, which were presented at different locations from the green bars. The task of observers was to discriminate which of the green bars was shorter than the other (Experiment 1) or whether the lengths of the green bars were equal or not (Experiments 2 and 3). One green bar producing apparent motion with the following shorter white bar was reported to be shorter than the other green bar producing apparent motion with the following longer white bar, not only when motion correspondence was determined on the basis of retinal proximity (Experiments 1 and 2),but also when motion correspondence was determined on the basis of nonretinotopic information-that is, a relative location within each perceptual group of bars (Experiment 3). These results indicate that motion processing involving object updating or motion deblurring in the nonretinotopic frame of reference is related to postdictive size modulation.

Parental Origin, DNA Structure, and the Schizophrenia Spectrum

Over the past 20 years, substantial evidence has accumulated that structural variations of the human genome, especially copy number variations, are important causal factors for schizophrenia and related disorders (1). Identification of associated copy number variations is shining new light on mechanisms of illness and on the genetically related spectrum of disorders (2) that may include not only bipolar disorder but also autism, mental retardation, and epilepsy (1). In this issue of the Journal, Ingason et al. (3) provide further data to suggest that neuropsychiatric conditions previously believed to be unconnected may share causal factors related to structural changes not visible on standard karyotype. Moreover, the parent of origin of the copy number variation in question, a duplication involving the proximal long (q) arm of chromosome 15, appears to be important.

Outgas 분석을 통한 MLCC Bar 변형률 측정

Busan RD Revised May 14, 2010; Accepted May 23, 2010)Abstract: MLCC (multi-layer ceramic capacitor) is usually fabricated by lamination of predetermined number of single layers. Often, the state of MLCC before sintering is called the green state, whose strength comes from the adhesion between the dielectric material and the polymer binder. Therefore the lamination of a single layer before sintering can be easily deformed by environment due to the relatively lower strength. After the compression process, which helps single sheets cohereto with adjacent sheets, the MLCC green bar is preheated to resolve the probable internal stress. Unfortunately, unexpected deformation after preheating resulted in problems during cutting of the MLCC green bar. In this study, one of 2 primary hypotheses which were proposed to resolve the unexpected deformation after preheating was examined by quantitative experiment with GC/MS (gas chromatograpy/mass spectrometer). The proportion of deformation caused by DOP evaporation, which was primarily evaporated componet during preheating, to the total deformation of the MLCC green bar was found to be 53%.Keywords: GC/MS, Outgas, Deformation, DOP, MLCC compressed bar

Watching the brain oscillating : A neural correlate of illusory jitter

Moving borders defined by small luminance changes (or by colour changes), placed in close proximity to moving borders defined by large luminance changes, can appear to jitter at a characteristic frequency (Arnold & Johnston, 2003). To reveal the neurophysiological substrates of this illusion we measured brain activity using magnetoenceohalography (MEG). In conditions 1–3, vertical green bars, superimposed upon larger red squares, moved across a black background. The green bars were either (1) darker, (2) isoluminant with, or (3) brighter than the red squares. In condition 4, vertical green bars moved across an isoluminant red background. In condition 5, physical jitter was added to dark green bars centered in a moving red square to mimic illusory jitter. In conditions 1-4, subjects indicated if the green bar appeared to jitter. If illusory jitter was reported, subjects then matched the illusory jitter rate to the frequency of an adjacent physical jitter. The matched frequency for each subject was used in condition 5. Illusory jitter was only perceived in condition 2 and its frequency was ~10 Hz. We also found that neural oscillations around 10 Hz were significantly enhanced in condition 2 relative to all other conditions. As these oscillations were enhanced relative to isoluminant motion (condition 4) and physical 10 Hz jitter (condition 5), we believe that the enhanced activity is related to illusory jitter generation rather than to jitter perception or to isoluminant motion per se, supporting our hypothesis that MISC is generated within cortex by a dynamic cortical feedback circuit.

Metabolomic Changes Accompanying Transformation and Acquisition of Metastatic Potential in a Syngeneic Mouse Mammary Tumor Model

Breast cancer is the most common cancer type for women in the western world. Despite decades of research, the molecular processes associated with breast cancer progression are still inadequately defined. Here, we focus on the systematic alteration of metabolism by using the state of the art metabolomic profiling techniques to investigate the changes of 157 metabolites during the progression of normal mouse mammary epithelial cells to an isogenic series of mammary tumor cell lines with increasing metastatic potentials. Our results suggest a two-step metabolic progression hypothesis during the acquisition of tumorigenic and metastatic abilities. Metabolite changes accompanying tumor progression are identified in the intracellular and secreted forms in several pathways, including glycolysis, the tricarboxylic acid cycle, the pentose phosphate pathway, fatty acid and nucleotide biosynthesis, and the GSH-dependent antioxidative pathway. These results suggest possible biomarkers of breast cancer progression as well as opportunities of interrupting tumor progression through the targeting of metabolic pathways.

Integrative genomic analyses of neurofibromatosis tumours identify SOX9 as a biomarker and survival gene

Understanding the biological pathways critical for common neurofibromatosis type 1 (NF1) peripheral nerve tumours is essential, as there is a lack of tumour biomarkers, prognostic factors and therapeutics. We used gene expression profiling to define transcriptional changes between primary normal Schwann cells (n = 10), NF1-derived primary benign neurofibroma Schwann cells (NFSCs) (n = 22), malignant peripheral nerve sheath tumour (MPNST) cell lines (n = 13), benign neurofibromas (NF) (n = 26) and MPNST (n = 6). Dermal and plexiform NFs were indistinguishable. A prominent theme in the analysis was aberrant differentiation. NFs repressed gene programs normally active in Schwann cell precursors and immature Schwann cells. MPNST signatures strongly differed; genes up-regulated in sarcomas were significantly enriched for genes activated in neural crest cells. We validated the differential expression of 82 genes including the neural crest transcription factor SOX9 and SOX9 predicted targets. SOX9 immunoreactivity was robust in NF and MPSNT tissue sections and targeting SOX9 – strongly expressed in NF1-related tumours – caused MPNST cell death. SOX9 is a biomarker of NF and MPNST, and possibly a therapeutic target in NF1.

Synthesis and densification behaviour of magnesium aluminate spinel: Effect of Dy 2O 3

Magnesium aluminate spinels have been developed by reaction sintering of calcined alumina and calcined magnesia and its densification behaviour was studied in presence of Dy 2O 3. Green bar made from stoichiometric spinel composition with and without Dy 2O 3 were subjected to dilatometric study, densification study and microstructural evaluation by SEM. It was found that Dy 2O 3 additive does not have significant effect on the spinelisation but favours the densification of the spinel. Microstructure of sintered spinel without any additive is non-uniform with some exaggerated grain growth. Dy 2O 3 prevents the exaggerated grain growth and thereby helps in the densification process.

Image reconstruction from optical interferometric data

Generating images of astronomical sources is a significant challenge for optical interferometry, although this is routinely done for similar observations using radio telescopes. One needs to measure both the ‘fringe-visibility’ amplitude and phase of the incident light waves. However, while the atmosphere usually changes on long timescales at radio wavelengths, in the optical the fluctuations are on the order of a few milliseconds, thus resulting in corrupted fringe-visibility phases. One particular image-reconstruction approach that has recently benefited from significant improvement1, 2 uses the square of the visibility amplitude and the so-called closure phases. A closure phase is the sum of the visibility phases around a triangle of interferometer baselines, resulting in the cancellation of atmospheric-turbulence effects. This technique has reliably reproduced test images,3 but it also leads to the loss of a fraction of the phase information and can reduce the signal-to-noise ratio of the final images. Therefore, one of themajor challenges is the development of techniques that recover as much phase information as possible. We have been working on the generation of such techniques for use with the Navy Prototype Optical Interferometer (NPOI). An important recent achievement is the implementation of an integration method4, 5 that first aligns the phases of the 2ms interferometric observations and subsequently adds the data frames coherently over much longer timescales. This technique increases the observational signal-to-noise ratio and retains the maximum phase information. We have also improved two methods aimed at correcting the observed phases for atmospheric effects. We first developed a differential phase technique6 to recover the phase information Figure 1. Images of the Hα hydrogen emission of the eclipsing binary star β Lyrae at orbital phases of 0.24 (left) and 0.78 (right). The movement of the Hα emission relative to the continuum photocenter (green dots) is evident. The elongation of the Hα images is caused by the shape of the image-reconstruction beam. The green bar corresponds to 2 milliarcseconds.

Hearing Preservation in Patients With a Cochlear Implant

Hearing Preservation in Patients With a Cochlear Implant

Iowa gambling task: Administration effects in older adults.

The Iowa Gambling Task (IGT) assesses decision-making.ObjectiveThe objective of the present study was to investigate whether specific changes in administering the IGT can affect performance of older adults completing the task.MethodThree versions of the IGT were compared regarding the feedback on the amount of money won or lost over the course of the test. The first version (I) consisted of a replication of the original version (Bechara et al., 1994), which utilizes a computerized visual aid (green bar) that increases or decreases according to the gains or the losses. The second version (II), however, involved a non-computerized visual aid (cards) and, in the third version (III) the task did not include any visual aid at all. Ninety-seven older adults, divided into three groups, participated in this study. Group I received computerized cues (n=40), group II, non-computerized cues (n=17) and III was submitted to a version without any cues (n=40).ResultsThe participants without any cues achieved only a borderline performance, whereas for those with non-computerized cues, twice the number of participants showed attraction to risk in relation to those with aversion. The participants of the computerized version were homogeneously spread across the three performance levels (impaired, borderline and unimpaired).ConclusionsAspects of the complexity of the decision process as well as of the task used are proposed as possible theoretical explanations for the performance variation exhibited.

Age and Time Need Not and Should Not Be Eliminated From the Coronary Risk Prediction Models

Risk assessment, risk communication, and risk management are 3 fundamental steps in the primary and secondary prevention of coronary heart disease (CHD). Consequently, national and international guidelines1–4 have been formulated to assist clinicians in providing standardized care for treating coronary risk factors. These guidelines are consistent with the best available scientific evidence on risks of developing CHD and potential strategies to reduce those risks via nonpharmacological and pharmacological interventions. One of the critical concepts on which contemporary guidelines are founded is the notion that the choice and intensity of an intervention strategy should in part be based on the underlying risk—ie, the absolute risk of experiencing a CHD event during a short-term period. This is typically estimated as the 10-year risk of CHD for a man or a woman of a specific age.1,3,4 In this issue of Circulation , Ridker and Cook5 present an argument to eliminate both the age and the time dependency of CHD risk prediction algorithms. On the basis of the objectives of current guidelines and risk prediction algorithms, we disagree with the suggestion made by Ridker and Cook. We submit that not only is removal of age and time from the risk prediction equations not necessary, but, to the contrary, such removal may be inappropriate. Furthermore, as we demonstrate below, the objectives desired by Ridker and Cook are already available with the existing prediction algorithms and often have been incorporated into the standard use of the current guidelines. See p 657 Before we proceed, it would be useful to summarize the observations made by Ridker and Cook. First, they point out the possibility that young individuals with multiple risk factors and very low short-term CHD risk but a much higher lifetime CHD risk (patient example 1 in their article) may not be targeted …

Compression of Visual Space before Saccades

We studied how the human visual system recalibrates visual coordinates to compensate for saccadic eye movements. Observers made 20 horizontal saccades to a target on an otherwise featureless red screen, and reported the apparent position of a vertical green bar that was briefly displayed before, during, or after the saccade. Bars presented 50 ms before the beginning of the saccade, or after its completion, were perceived accurately and veridically. However, bars presented immediately prior to the saccade were systematically mislocated, either in the direction of the saccade or in the opposite direction, depending on the spatial position of the bar. This result has been verified by various techniques including Vernier offset estimation, and a forced-choice annulling task. When four bars (straddling the saccade target) were displayed in the interval −25 to 0 ms, they were seen to be merged into 1 bar (forced choice). None of these effects could be mimicked by causing the scene to move at saccadic speeds and amplitudes. The results suggest that each saccade is accompanied by a non-visual signal that displaces the retinal coordinate system, and a momentary compression of visual space. The perceptual compression may be instrumental in ensuring a smooth transition from fixation to fixation.